Jeff,
Why not create a separate site along the lines of CareerAdvice for these types of questions?
I say this because the general question is not specific to CompSci... A relative of mine had been in engineering (ME or EE, I think) and decided after 10+ years in the field that it was of no interest to him... he ended up getting a career in a completely different field.
Another relative was quite determined to go into a pharmacy, but ended up going into psychology, for similar reasons (though thankfully the decision was made prior to the X years of experience).
I could just as easily envision people asking for advice with jobs (bad culture, bad boss, bad whatever), with specific career paths (I'm good, but company isn't, should I consider starting my own business... should I get into management.. etc), or with moral dilemmas (execs that need to withhold info regarding upcoming mergers, etc).
The only real concern would be adjusting the SO/SE platform that creates/enforces some level of anonymity, to avoid undesirable name/profile association between sites (SO, LinkedIn, etc)

I get a surprising number of emails from career programmers who have spent some time in the profession and eventually decided it just isn't for them. Most recently this: I finished a computer science degree last year, worked about a year in the Java EE stack. I liked requirements engineering ...

I disagree with your assessment. Nor do I feel that it's difficult to MEASURE the productivity. The issue as I see it, is that most developers DON'T measure their work.
Measuring software is simple. Unit tests measure results. You can create a new BDD test for new FEATURES, and you can create unit tests to confirm specific edge cases within the feature, and you can create performance tests to confirm the QUALITY of the results (runtime, CPU usage, memory usage, etc).
The simple issue, is that very few people bother writing tests. And few people also know HOW to write GOOD tests.
Once these tests exist, it's easy to say that both Peter and Frank successfully PRODUCED code that met the BUSINESS requirement, but that Peter's code provided a superior result by: improving performance (let's assume that deleted code leads to reduced execution time, plus Frank's solution probably added to the memory requirements), AND it was likely a MEASURABLE improvement to maintainability by improving the code coverage (since there's now LESS code to cover with tests).
Unfortunately, it seems that a lot of developers do not come from a development background (Comp Sci, Soft Eng, whatever the term)... I see more developer resumes with other backgrounds (psychology, biology, criminal science, etc)... and it seems that ONLY the people with a dev background are interested in PROVING their productivity. The rest of the people just like writing code to solve a puzzle. All fine and good for most business needs, but THAT is the source of your "no such thing as software productivity".

Bill Caputo, through repeated conversations we've had, has convinced me of something very surprising. It was something that changed the way I think about the world, and how I do my job. There is no such thing as software productivity. As Martin Fowler observed almost a decade ago, productivity i...

About a year and a half ago, I researched the state of routers: about as unsexy as it gets but essential to the stability, reliability, and security of your Internet connection. My conclusion? This is boring old plain vanilla commodity router hardware, but when combined with an open source fi...